A bacterium that has led to the death of four people is known to have been tested positive in a closed Texas food processing plant, the U.S. Food and Drug Administration said.

After State laboratory results showed Listeria monocytogenes, a bacteria that can cause severe illness, in chopped celery at the plant, The Department of State Health Services ordered SanGar, the Texas plant to shut down immediately and recall products shipped from its San Antonio plant, back from January.

Carrie Williams, a department spokeswoman said the four of them contracted listeriosis after consuming celery that had been processed at the SanGar plant.

About ten patients with the diseases were studied over an 8-month period; six of them were linked to the celery made at the SanGar plant.

The premises of the plant were investigated and FDA found the bacteria in processed celery in different parts of the plant. The listeria found in samples "matches the DNA fingerprint of the clinical cases of listeriosis reported by the Texas Department of State Health Services," the FDA said in a statement.

However another independent test at Quanta Lab of Selma, Texas, came back negative after testing the celery.
"The FDA and the State have not turned over to us the documentation supporting their findings," Galvan said.
The company also brought a listeria expert to look at protocols, said Galvan. Galvan also said that around 100 SanGar workers were idled due to the closing of the plant. "We're pretty optimistic about having the company up and running before the hearing," the attorney said. "We're not going the litigation route."

Earlier in October, the company said it had an excellent record of safety and health over the past three years.
The authorities however found the bacteria in chopped celery and said it could have contaminated other products in the plant. The plant is involved in making a range of products, including lettuce, peppers, carrots, cucumbers, as well as salad vegetables; and the company said they were distributed in sealed packages.

Besides the bacteria, inspectors found a condensation leak above a food product area, dirt on a food-preparation table, and hand-washing problems at the San Antonio plant, the state health department said.

The bacteria have been tied to listeriosis, which sickens about 2,500 Americans and contributes to the death of 500 people annually, the CDC reports.

The Texas health department is now taking the investigation seriously.